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My dealer did the vehicle handover reset for me last week and all was fine, but the problem returned 6 days later, so I reset the PCM myself this afternoon. Too soon to know if the fix is really a fix.
Neither the dealer nor I needed to ask for an XM refresh signal following the reset -- the satellite radio station presets (along with nav history and destinations, AM and FM presets, cellphone connection, etc.) were erased, but XM connectivity itself never seemed to have been lost. Based on what I've read, it doesn't seem to matter whether or not you get an XM refresh signal, but I could be wrong.
My XM worked as soon as I did the reset but I sent the refresh signal anyway because it was the free trial period (the reason this whole thing happened) and I wanted to be sure it would keep working after they stopped it.
Like I said, not sure if it makes a difference but worth a try for anyone who's had the gremlins return.
the car spent the night at porsche and i picked it up yesterday afternoon. the two recall issues were addressed (heat shield and fuel tank pressure sensor) and the PCM has not had any rebooting issues.
I received an email today from PCNA addressing this issue. Looks to be the same resolution as has already been discussed in this thread.
Dear Mr. Evans,
We are aware that some of our customers are experiencing an issue with their vehicle’s central communication unit, known as the Porsche Communication Management (PCM), causing it to continuously reboot. If your vehicle is equipped with PCM and you are experiencing this condition, performing a hard reset of the PCM should resolve the concern. To perform this reset please follow these steps: ***Before performing this procedure, ensure that your vehicle is located outdoors. Please note that hard resetting the PCM will remove all personalized settings
Press and hold the INFO button for approximately 10 seconds until the PCM reboots.
Press the CAR button.
Press the OPTION button or touch the tab of the same name in the header.
Select "SET PCM system">>"Reset PCM".
Select "Vehicle handover" This resets all settings to predefined values and deletes your personal settings and data (including addresses, destinations, radio stations, phone numbers, as well as the recordings in the Sport display).
Confirm the relevant prompt by selecting "Yes".
If after performing this procedure your vehicle continues to experience consistent reboots please contact your local authorized dealership to schedule an appointment for further diagnosis.
I got this same email from info@porsche.us yesterday. This is the day after I searched the internet on my own and discovered the fix. And, that this is not the first time xm radio updates have caused this issue. What is really odd is that in this recent email they tell you to "ensure your vehicle is located outdoors", but don't say anything about a SiriusXM update as the cause or that you will have to also "refresh" your SiriusXM radio (go to: https://care.siriusxm.com/retailrefr...#/refreshradio ). Without this explanation makes one wonder why the vehicle should be located outdoors while resetting the PCM - ... danger of explosion???? ;-)
Well my issue returned and it’s worse. After the reset and being fine for a week it came back. Now I can’t even do the reset. When I press INFO after about 8 seconds the whole reboot occurs and I can’t even get the option to do the reset and factory handover etc. Tried at least 5-6 times. Anyone else experience this? Now I’m frustrated. I drove last night no issue. And today an issue.
Unit might be extremely hot (it reboots as part of heat protection) and is resetting faster than you can do the handover reset steps.
Try pulling the fuse and letting it sit for an hour or so to cool down. Then put the fuse back in, turn the car on and try doing the handover reset steps and see if the cool down period buys you enough time.
Driver's footwell fuse panel. 25 Amp fuse in the first solid row of fuses (Row B)
I have not driven my 2014 991.1 w/active SiriusXM subscription since before this issue started. Intentionally have not driven it until today after hearing of all of the problems. One hour drive. No issues. Navigation, Sat Radio, phone, etc all worked normally with no issues.
Car was locked and on a trickle charger the whole time.
I pulled the rubber access plug underneath the XM antenna wart and disconnected the coax connector. Better safe than sorry, until somebody figures out whether this is still happening and what to do about it.
I pulled the rubber access plug underneath the XM antenna wart and disconnected the coax connector. Better safe than sorry, until somebody figures out whether this is still happening and what to do about it.
Unit might be extremely hot (it reboots as part of heat protection) and is resetting faster than you can do the handover reset steps.
Try pulling the fuse and letting it sit for an hour or so to cool down. Then put the fuse back in, turn the car on and try doing the handover reset steps and see if the cool down period buys you enough time.
Driver's footwell fuse panel. 25 Amp fuse in the first solid row of fuses (Row B)
appreciate it. But I doubt it was hot. Was in my garage and cool out. I’ll try this later but am pessimistic. 😬
appreciate it. But I doubt it was hot. Was in my garage and cool out. I’ll try this later but am pessimistic. 😬
the cpu in the unit could definitely be hot from rebooting over and over and the sooner you pull that fuse and let it cool down the better for the electronics in there.
(worst case, replacement units on ebay are in the $1200-1500 range)
Disclaimer: I have a 981 Boxster, not a 991, so while the hardware will be the same I don't know if it is equally easy to access. On the Boxster it's pretty obvious how to get to the necessary wiring, because there's a large removable rubber piece in the underside of the trunk lid directly opposite the antenna wart.
Assuming you can gain access to the antenna connector, you can disconnect it by pressing on the tab shown here:
Pull the two halves apart and it will look like the photo above. On my car, the connector was wrapped in something akin to pipe insulation. It can be slid back along the wire as seen here.
Afterward, you will get an error message ("CHECK XM ANTENNA") if you try to select XM Radio on the PCM. Navigation should still work (this antenna is only for XM, not GPS), but the color-coded traffic overlays won't be visible.
05-29-2020, 11:10 PM
